Chill for direct casting of thin platelets

ABSTRACT

Apparatus for successively casting discrete thin platelets of metal includes a rotating internally fluid cooled cylindrical chill arranged so that the lower portion of its surface dips into molten metal. The chill surface is formed of successive circumferential areas of metal chill separated by circumferential areas of refractory material on which the molten metal does not solidify. A scraper is positioned to remove the solidified platelets from the chill and discharge them into a cooling medium.

United States Patent Paliwoda 1 July 4, 1972 54 CHILL FOR DIRECT CASTING 0F THIN 2,561,636 7 1951 Pyk ..164/87 x PLATELETS 3,540,517 11/1970 Wojcik et al ..164/87 X [72] Inventor: Eugene J. Paliwodl, Bethel Park, Pa. primary Emminer ROben g m [73] Assignee: Jones 81 Laughlin Steel Corporation, Pitt- A"0mey G' and sburgh, P31 22] Filed: June l8, 1?") [57] ABSTRACT Apparatus for successively casting discrete thin platelets of APPL 47,373 metal includes a rotating internally fluid cooled cylindrical [52] US. Cl ..l64/27l, 164/130 arranged so lower P 0f its Surface p [51] ML Ci. I I I I I an 15,04,132 23/04 molten metaL The chill surface is formed of successive cir- 53] n w oi Search 164/1 30' 325 344 276 87 cumferential areas of metal chill separated by circumferential 64/127 1:373 areas of refractory material on which the molten metal does not solidify. A scraper is positioned to remove the solidified Rfiffirences Clied platelets from the chill and discharge them into a cooling d' UNITED STATES PATENTS me 189,887 4/1877 Blake 164/127 X 5 Claims, 4 Drawing Figures PATENTEDJUL' 4 I972 3, 674, 084

sum 1 or 2 INVENTOR EUGENE J. PALIWODA his ATTORNEY PATENTEDJIJL 41972 3, 574,0 4

SHEET 2 BF 2 Fig. 3

"NE NTDR EUGENE J. PALIWODA his ATTORNEY CHILL FOR DIRECT CASTING OF THIN PLA'I'ELETS Efforts have been made extending over many years to produce metal strip directly from molten metal by freezing a thin layer of metal on a moving chill surface such as a drum or belt. While strip of relatively low melting point metals is produced in this way with some success, strip of high melting point metal such as steel is difficult to make on a commercial scale. One problem is the maintaining of uniform strip thickness. This problem and a solution therefor is described in detail in US. Pat. No. 3,345,738. Another problem concerns the strip edge, which tends to be ragged. Because of the various problems inherent in this process, consideration is now being given to a modified process in which discrete thin platelets of steel are produced directly from molten metal. These platelets are then stacked and rolled together under conditions such that they weld. Such a process is described in a general way in US. Pat. No. 2,383,766.

It is an object of my invention to provide apparatus for casting discrete thin platelets of high melting point metal such as steel directly from molten metal. It is another object to pro vide such apparatus including a chill on which the molten metal solidifies in discrete platelike elements. It is another object to provide such apparatus making use of a rotating cylindrical chill surface. Other objects of my invention will appear in the description thereof which follows:

An embodiment of my invention presently preferred by me is illustrated in the attached figures to which reference is now made.

FIG. 1 is a vertical cross section through apparatus of my invention.

FIG. 2 is an elevation in cross section on the plane 2--2 of FIG. 1.

FIG. 3 is a plan of the cylindrical chill employed in the apparatus of FIGS. 1 and 2.

FIG. 4 is an elevation of chill of FIG. 3, together with the collar fixing means described hereinafter.

A refractory lined crucible having opposite end walls 11 and 12 respectively, is disposed to hold a bath of molten metal 13. End wall 11 extends above the surface of molten metal 13 and supports a shaft bearing 14. Opposite thereto end wall 12 likewise supports a shaft bearing which is aligned with bearing 14. Bearings 14 and 15 are preferably split bearings. In bearing 14 is journaled shaft 16 which is fixed axially to one end 18 of hollow drum 17. l-Iollow shaft 20 is likewise afiixed to the other end 21 of drum l7. Hollow shaft 20 is journaled in shaft bearing 15.

Through hollow shaft 20 pipe 23 extends into the interior space of drum 17. Pipe 23 is open on its inside end and is also provided with holes 2424 over that portion of its surface which is inside drum 17. The outer end of shaft 20 fits into stationary cap 25 which is provided with a drain opening 26. Pipe 23 extends through the end of cap 25 and is connected to a source of cooling fluid not shown.

Drum 17 is provided with a disk-shaped refractory collar 27 contiguous to its end 18 and a similar disk-shaped refractory collar 28 contiguous to its end 21. The two collars are of the same diameter, which is somewhat greater than the external diameter of drum 17. A dished circular plate 30 is positioned over shaft 16 against collar 27 and is maintained in that position by helical spring 31 which is compressed between the inner surface of shaft bearing 14 and plate 30. A like dished plate 32 is positioned against collar 28 and held in place by helical spring 33.

One side of crucible 10 is provided with an inclined filler spout 35, the open end of which is positioned above the level of molten metal in the crucible. The upper surface of spout 35 extends downwardly into a wall 36 which is positioned to be below the normal level of metal in the crucible 10. The crucible ends 11 and 12, side wall 36 and side wall 37 opposite thereto support a cover 39 which entirely encloses drum l7 and the metal in crucible 10. Pipe 40 opens into cover 39 in the wall 41 thereof which rests on crucible wall 36. In the op posite wall 42 of cover 39 is positioned a downwardly inclined discharge chute 43. The bottom surface 44 of discharge chute 43 extends into cover 39 and makes contact with the outer surface of drum 17 as scraper 45. The lower end of discharge chute 43 extends into receptacle 47 which is filled with water. The tip 48 of the upper surface of discharge chute 43 extends below the level of the water in receptacle 47.

The circumferential wall of drum 1'! is made of high thermal conductivity metal such as copper. In this wall are embedded transverse refractory elements 50-50 parallel to the axis of drum 17. These elements are preferably of inverted wedge cross section and dovetail into mating slots so that they are timily held in the wall of drum 17. The elements 50 extend the full length of drum 17 and abut the end pieces 27 and 28. The outer surfaces of elements 50 are flush with the outer surface of drum 17, and alternate circumferentially with exposed portions 52 of the drum surface.

The operation of my apparatus will now be described with respect to the embodiment illustrated. The crucible 10 is filled with molten metal to a level such that it extends above the edge of bottom wall 36 and immerses a portion of the lower circumference of drum 17. A nonoxidizing gas is introduced into cover 30 through pipe 40. Shaft 16 is rotated by driving means not shown so that drurn 17 rotates counter-clockwise in FIG. 2. Cooling fluid, preferably water, is introduced into the interior of drum 17 through pipe 23 and sprays out through holes 24 and the open end of pipe 23. The water is drained from the drum through hollow shaft 20. The cooling water drains from pipe 20 through drain opening 26 in cap 25. As drum 17 rotates a portion of its lower surface makes contact with the molten metal 13. This metal is chilled by the metal portions 52 of drum 17 but not by the refractory elements 50 which are poor conductors of heat. As drum 17 rotates, therefore, the chill sections 52 in contact with the molten metal are lifted above die metal level, carrying with them the metal which has solidified against them. These solidified metal platelets 51-51 are carried around on the circumference of drum 17 as it rotates until they are dislodged by scraper 45 and slide down the inclined bottom 44 of discharge chute 43 into the water held in container 47. They are allowed to remain in container 47 until they are cool enough to remove.

The nonoxidizing gas introduced through pipe 40 prevents oxidation of the hot platelets 51 while they are inside cover 39 and chute 43. They are discharged from chute 43 directly into the water contained in receptacle 47 without coming in contact with the air and so cool to a low temperature without oxidizing. The water in container 47 and the molten metal in the bottom of filler spout 35 seal container 39 so that atmospheric air does not enter.

Collars 27 and 28 are not affixed to drum 17 but are held in place by the compression springs 31 and 33 and end plates 30 and 32 above described. When it is necessary to replace refractory elements 50 the cover 39 is removed and the drum 17 and its associated apparatus are lifted out of shaft bearings 14 and 15. The end pieces 27 and 28 are then slid off the ends of their respective shafts and the refractory wedges 50-50 are slid out of their grooves and replaced by new ones.

lclaim:

1. A chill adapted to solidify molten metal from a bath thereof to a plurality of individual discrete platelets including a convex hot surface which is moved through the molten metal bath and a cold surface to which cooling fluid is applied, in which the hot surface comprises discrete areas of high thermal conductivity metal against which molten metal freezes and alternating discrete areas of low thermal conductivity material against which the molten metal does not freeze arranged to be carried successively through the bath by the movement of the hot surface.

2. The chill of claim 1 in which the surfaces of the successive areas of high and low then'nal conductivity material are flush.

3. The chill of claim 1 in which the hot surface is cylindrical and the successive alternating areas of high and low thermal conductivity material are spaced around the surface of the cylinder and extend over its length.

4. The chill of claim 1 in which the high thermal conductivity material is metal and the lower thermal conductivity material is a refractory.

5. The chill of claim 2 in which the hot surface and the successive alternating areas of high thermal conductivity are 5 metal and the successive alternating areas of low thermal conductivity material comprise refractory elements embedded in the hot surface.

* i l t i 

1. A chill adapted to solidify molten metal from a bath thereof to a plurality of individual discrete platelets including a convex hot surface which is moved through the molten metal bath and a cold surface to which cooling fluid is applied, in which the hot surface comprises discrete areas of high thermal conductivity metal against which molten metal freezes and alternating discrete areas of low thermal conductivity material against which the molten metal does not freeze arranged to be carried successively through the bath by the movement of the hot surface.
 2. The chill of claim 1 in which the surfaces of the successive areas of high and low thermal conductivity material are flush.
 3. The chill of claim 1 in which the hot surface is cylindrical and the successive alternating areas of high and low thermal conductivity material are spaced around the surface of the cylinder and extend over its length.
 4. The chill of claim 1 in which the high thermal conductivity material is metal and the lower thermal conductivity material is a refractory.
 5. The chill of claim 2 in which the hot surface and the successive alternating areas of high thermal conductivity are metal and the successive alternating areas of low thermal conductivity material comprise refractory elements embedded in the hot surface. 